;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; PROCEDURE KEPDEMO   ;;;
;;; By Darrin Casebeer  ;;;
;;;    Kevin Tubbs      ;;;
;;;    Summer 98        ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;

PRO kepdemo

a=4
ecc=0.5
TimeSlice=400d

A1=0d
A2=0d

base = WIDGET_BASE(TITLE='Example of Keplers Law equal Area in Equal Time',XSIZE=270,YSIZE=400,/COLUMN)

  row1=WIDGET_BASE(base,/row)
  axisid = CW_FIELD(base,TITLE="Semimajor axis     ",/FLOAT,/FRAME,$
  VALUE=a,$
  /ALL_EVENTS)
  row2=WIDGET_BASE(base,/row)
  eccid = CW_FIELD(base,TITLE="Eccentricity       ",/FLOAT,/FRAME,VALUE=ecc,$
  /ALL_EVENTS)
  row3=WIDGET_BASE(base,/row)
  tid = CW_FIELD(base,TITLE="Time in one Slice  ",/FLOAT,/FRAME,$
  VALUE=TimeSlice,$
  /ALL_EVENTS)
  row4=WIDGET_BASE(base,/row)
  drawid = WIDGET_BUTTON(base,VALUE="Draw Elipse",/ALIGN_CENTER,XSIZE=270,YSIZE=50)
  ENDid=WIDGET_BUTTON(base,VALUE="END",/ALIGN_CENTER,XSIZE=270,YSIZE=50)
   WIDGET_CONTROL, base, /REALIZE
  REPEAT BEGIN
    ev=WIDGET_EVENT(base)
    CASE ev.id OF
    axisid: a=ev.value
    eccid:  ecc=ev.value
    tid:    TimeSlice=ev.value
    drawid: BEGIN
              keplers,base,a,ecc,TimeSlice,A1,A2
              PRINT,A1,A2
              base2 = WIDGET_BASE(TITLE='Areas',XSIZE=270,YSIZE=150,/COLUMN)
              row5=WIDGET_BASE(base2,/row)
              Area1 = CW_FIELD(base2,TITLE="Area in Slice 1 ",/FLOAT,/FRAME,$
              VALUE=A1,$
              /NOEDIT,/ALL_EVENTS)
              row6=WIDGET_BASE(base2,/row)
              Area2 = CW_FIELD(base2,TITLE="Area in Slice 2 ",/FLOAT,/FRAME,$
              VALUE=A2,$
              /NOEDIT,/ALL_EVENTS)
              WIDGET_CONTROL, base2, /REALIZE
            END
    ENDid:  BEGIN
 	      WDELETE
              WIDGET_CONTROL,base,/DESTROY
              WIDGET_CONTROL,base2,/DESTROY
              RETURN
            END
    ELSE:
    ENDCASE
   END UNTIL ev.id EQ ENDid
   RETURN
END